WASHINGTON — President Donald Trump’s selection of his White House doctor to run the massive Department of Veterans Affairs triggered concern Thursday among lawmakers and veterans groups about whether he has the experience to manage an agency paralyzed over Trump’s push to expand private care.

Ronny Jackson, a Navy rear admiral entrusted with the health of the past three presidents, is a lifelong physician whose positions on privatizing operations in the second largest federal department and addressing ballooning health care costs are unknown. First named to the top White House post by President Barack Obama, he would be new to running a big bureaucracy if given leadership over a department of 360,000 employees serving 9 million veterans.

In a statement, Trump praised Jackson as “highly trained and qualified.” But representatives of veterans aren’t sold on the choice, or on Trump’s decision a day earlier to fire VA Secretary David Shulkin.

“There is little that we know about Dr. Ronny Jackson’s vision and qualifications,” said Paul Rieckhoff, founder and CEO of Iraq and Afghanistan Veterans of America. “Our concern is whether President Trump was more interested in picking a secretary who would be politically loyal rather than someone who can work across the aisle to fix long standing problems of bureaucratic delay.”

Similar doubts were expressed by Veterans of Foreign Wars, which praised Jackson’s military background in a statement but pointed to a nominee biography devoid of “any experience working with the VA or with veterans, or managing any organization of size, much less one as multifaceted as the Department of Veterans Affairs.” AMVETS echoed such sentiments.

“We look forward to a rigorous confirmation hearing,” Rieckhoff said.

Montana Sen. Jon Tester, top Democrat on the panel that will consider the nomination, said he had yet to determine if Jackson “is up to the job.”

It’s not clear from Jackson’s military service record how much, if any, management experience he has. His military assignments did not appear to include supervision over a large department or unit. His Navy biography says he deployed to Iraq with a Marine unit and served as the emergency physician in charge of resuscitative medicine for a trauma platoon.

Jackson joined the White House medical team in 2006 and is perhaps best known for his appearance before the press corps in January, announcing the results of Trump’s first physical in a performance that showed he was quick-witted and unfailingly complimentary of Trump.

Marveling at the 71-year-old president’s good health, Jackson opined, “It’s just the way God made him.”

A White House official said Shulkin himself had recommended Jackson for an undersecretary position at the VA in the fall, and Trump ultimately decided he was more comfortable with Jackson than with other top candidates. The official was not authorized to discuss personnel matters and spoke on condition of anonymity.

If confirmed by the Senate, Jackson would face immediate crises, like a multi-billion dollar revamp of electronic medical records now in limbo that members of Congress fear will prove too costly and wasteful, and a budget shortfall in the coming weeks in its private-sector Veterans Choice program.